While day driving on a clearly marked interstate in slightly hazy weather from fires, the car suddenly, unprompted, steered to the left without any warning or any indicators going off. This caused the car traveling at highway speed to crash into a barrier wall, drive half way up before driver could regain control of the steering and then spun out across 4 lanes of traffic. Driver said cars lane assist was on and it was ping ponging for a moment before it suddenly steered to the left unprompted causing the crash. A witness behind stated they saw the car behave the same as did the two passengers in the car.